How to select scale x,y,z keyframes all at once in graph editor
In the Graph Editor, on the right side you will see the sidebar that shows you all objects and items that have some animation attached to it. Select your object from that list and make sure to widen the drop menu of it beside its name. There you will see the different axis. Using Shift select all of the. Next in the actual editor press A once or twice so all handles are selected and then press S to scale all of them.